I've done some research on this matter and can confirm that the 3rd Michigan was one of the units that was was dispatched to San Antonio in the summer of 1865. They were mustered out there around Feb. 1, 1866. The details of the unit's activity during that period is sketchy, but it seems that they did patrol in south Texas and along the border with Mexico. This would have been aimed at intercepting some ex-Confederates trying to escape to Mexico as well as frontier Indian patrols.

In his book, "Custer in Texas", John M. Carroll recounts the story of the so-called 'mutiny' of the 3rd Michigan Cavalry in which the unit, well known for its spit and polish appearence, showed up at a special event with uniforms and equipment in total disarray. This behavior seems to have been a protest by a unit of volunteer soldiers who thought they should get to go home now that the war was over. Other than this one account--supposedly by a reporter of the New York Times-- I have been able to find very little about the 'mutiny.'

I own a M1860 Spencer Carbine that is identified to a soldier in Co. I of the 3rd Michigan and who most certainly was involved in all of this. I've taken a cursory look at newspapers from the period and not been able to find anything else about this unit in Texas. Most secondary sources I've checked that deal with the immediate post war period in Texas skip over military activity, although there are likely many I've overlooked.

In my opinion the question of volunteer soldier impatience with being mustered out at war's end is badly in need of some serious basic study.

Mike